一個簡單的nodejs連接mongodb示例，來自 mongodb官方示例
1. 創建package.json
首先，創建我們的工程目錄connect-mongodb，并作為我們的當前目錄
mkdir connect-mongodbcd connect-mongodb
輸入npm init命令創建package.json
npm init
然后，安裝mongodb的nodejs版本driver
npm install mongodb --save
mongodb驅動包將會安裝到當前目錄下的node_modules中
2. 啟動MongoDB服務器
安裝MongoDB并啟動MongoDB數據庫服務，可參考我之前的文章，或者MongoDB官方文檔
3. 連接MongoDB
創建一個app.js文件，并添加以下代碼來連接服務器地址為192.168.0.243，mongodb端口為27017上名稱為myNewDatabase的數據庫
var MongoClient = require('mongodb').MongoClient, assert = require('assert');// Connection URLvar url = 'mongodb://192.168.0.243:27017/myNewDatabase';MongoClient.connect(url,function(err,db){ assert.equal(null,err); console.log("Connection successfully to server"); db.close();});在命令行輸入以下命令運行app.js
node app.js
4. 插入文檔
在app.js中添加以下代碼，使用insertMany方法添加3個文檔到documents集合中
var insertDocuments = function(db, callback){ // get ths documents collection var collection = db.collection('documents'); // insert some documents collection.insertMany([ {a:1},{a:2},{a:3} ],function(err,result){ assert.equal(err,null); assert.equal(3,result.result.n); assert.equal(3,result.ops.length); console.log("Inserted 3 documents into the collection"); callback(result); });};insert命令返回一個包含以下屬性的對象:
在app.js更新以下代碼調用insertDocuments方法
var MongoClient = require('mongodb').MongoClient , assert = require('assert');// Connection URLvar url = 'mongodb://localhost:27017/myproject';// Use connect method to connect to the serverMongoClient.connect(url, function(err, db) { assert.equal(null, err); console.log("Connected successfully to server"); insertDocuments(db, function() { db.close(); });});在命令行中使用node app.js運行
5. 查詢所有文檔
添加findDocuments函數
var findDocuments = function(db,callback){ // get the documents collection var collection = db.collection('documents'); // find some documents collection.find({}).toArray(function(err,docs){ assert.equal(err,null); console.log("Found the following records"); console.log(docs); callback(docs); });};findDocuments函數查詢了所有'documents'集合中所有的文檔，將此函數添加到MongoClient.connect的回調函數中
var MongoClient = require('mongodb').MongoClient , assert = require('assert');// Connection URLvar url = 'mongodb://localhost:27017/myproject';// Use connect method to connect to the serverMongoClient.connect(url, function(err, db) { assert.equal(null, err); console.log("Connected correctly to server"); insertDocuments(db, function() { findDocuments(db, function() { db.close(); }); });});6. 使用過濾條件(query filter)查詢文檔
查詢'a':3的文檔
var findDocuments = function(db, callback) { // Get the documents collection var collection = db.collection('documents'); // Find some documents collection.find({'a': 3}).toArray(function(err, docs) { assert.equal(err, null); console.log("Found the following records"); console.log(docs); callback(docs); }); }7. 更新文檔
var updateDocument = function(db,callback){ // get the documents collection var collection = db.collection('documents'); // update document where a is 2, set b equal to 1 collection.updateOne({a:2},{ $set:{b:1} },function(err,result){ assert.equal(err,null); assert.equal(1,result.result.n); console.log("updated the document with the field a equal to 2"); callback(result); });};updateDocument方法更新滿足條件a為2的第一個文檔，新增一個b屬性，并將其設置為1。
將updateDocument方法添加到MongoClient.connect方法的回調中
MongoClient.connect(url,function(err,db){ assert.equal(null,err); console.log("Connection successfully to server"); insertDocuments(db,function(){ updateDocument(db,function(){ db.close(); }); });});8. 刪除文檔
var removeDocument = function(db,callback){ // get the documents collection var collection = db.collection('documents'); // remove some documents collection.deleteOne({a:3},function(err,result){ assert.equal(err,null); assert.equal(1,result.result.n); console.log("removed the document with the field a equal to 3"); callback(result); });};添加到app.js中
var MongoClient = require('mongodb').MongoClient , assert = require('assert');// Connection URLvar url = 'mongodb://localhost:27017/myproject';// Use connect method to connect to the serverMongoClient.connect(url, function(err, db) { assert.equal(null, err); console.log("Connected successfully to server"); insertDocuments(db, function() { updateDocument(db, function() { removeDocument(db, function() { db.close(); }); }); });});9. 創建索引
索引能夠改善應用的性能。下面你代碼在'a'屬性上添加索引
var indexCollection = function(db,callback){ db.collection('documents').createIndex({ a:1 },null,function(err,results){ console.log(results); callback(); });};更新app.js
MongoClient.connect(url,function(err,db){ assert.equal(null,err); console.log("Connection successfully to server"); insertDocuments(db,function(){ indexCollection(db,function(){ db.close(); }); });});代碼已經托管在碼云
總結
以上所述是小編給大家介紹的使用Nodejs連接mongodb數據庫的實現代碼，希望對大家有所幫助，如果大家有任何疑問請給我留言，小編會及時回復大家的。在此也非常感謝大家對VeVb武林網網站的支持！
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